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Earned Value Equations

Paul Naybour Paul Naybour

Published: 31st July 2013

Schedule Metrics

Schedule Performance Index (SPI)

SPI = earned value / plan value

Schedule Variance (SV)

SV = earned value – plan value

Schedule Variance (time)

SV(t)= Earned schedule – Actual time

Schedule Performance Index (time)

SPI(t)= Earned schedule / Actual time

Revised Estimated Duration

= Original planned duration / SPI(t)

Also used for target dates EVM 1 and EVM2

Cost Metrics

Cost Performance Index

CPI = earned value / COWD

Cost Variance

CV = earned value – COWD

Independent Estimate at



IEAC2=[(BAC-EV to date)/CPI 3 months]+COWD

IEAC3 = COWD + ((BAC – EV (cum)) / (CPI * SPI(t)))

IEAC4= COWD + ((BAC – EV (cum)) / (0.8CPI + 0.2SPI(t))

To complete performance measures

TCPI= Work remaining / Budget Remaining


TSPI = Work to complete with authority / planned remaining budget within authority

TSPI – (Authority – EV ) / ( Authority – PV )

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